With the development of mobile communication technologies, mobile phones have become necessary communication tools in our daily life. When using a mobile phone, the user often feels inconvenient when using the wired charging of the mobile phone. Currently, in the relevant art, many wireless mobile phone charging solutions have been proposed. Among these wireless mobile phone charging solutions, 13.56 MHz induction charging solution has been mature relatively. This solution merely requires to place a mobile phone on an induction base of a charger and can charge the mobile phone by means of induction without plugging. This convenient and rapid charging method has been appreciated by many mobile phone manufacturers. However, the design defect of the above wireless charging solution lies in that during mass manufacture, the key part in this solution, i.e., high permeability material, is easy to fail after long-term use, which brings risks into the charging process of the mobile phone. Therefore, although the wireless charging solution is much appreciated, it also makes many manufacturers have to take into account the quality problem of the product when employing the wireless charging solution.
FIG. 1 is a schematic diagram of a wireless charging protection circuit in the relevant art. As shown in FIG. 1, the wireless charging protection circuit includes: a wireless charging base 1 and a charging receiving circuit 2. The charging receiving circuit 2 may include: a high-permeability magnetic core 20. For the consideration of receiving antenna area, a receiving antenna is usually placed directly under the battery, and the antenna plane covers the battery. In order to prevent the influence on the battery from the alternating magnetic field generated during wireless charging and at the same time increase the magnetic flux of the receiving antenna coils, a layer of high-permeability ferrite is usually added between the battery and the receiving antenna coils. This layer of ferrite material is very important for the entire wireless charger. In fact, wireless charging technology generates an alternating magnetic field using a charging base, which magnetic field is coupled to the receiving coils at the back surface of the mobile phone by means of the coil antenna on the base, like an active power transmission transformer, and the high-permeability material is equivalent to a ferrite magnetic core of the transformer. With this high-permeability material, the magnetic flux of the receiving coils can be increased, thus improving the charging efficiency. In addition, if there is no high-permeability material layer, the alternating magnetic field will directly act on the surface of the battery of the mobile phone by transmitting through the receiving antenna. The surface layer of the battery is a metal layer, the metal layer will generate eddy current effects in the alternating magnetic field, that is, an eddy current is generated on the metal surface layer to generate an opposite magnetic field, which thus reduces the magnetic flux of the coils and severely affects the charging efficiency. Moreover, when the eddy current generated on the metal surface layer of the battery by the alternating magnetic field is big enough, it will bring hazards to the safety of the battery. In addition, the wiring on the main board of the mobile phone on the back of the battery will also be affected by the alternating magnetic field, for example, electromagnetic compatibility (EMC in short) problem will be very significant. Therefore, using a high-permeability magnetic core in the wireless charging solution of the mobile phone is a necessary option.
However, the problems existing in the relevant art lie in that when this layer of ferrite material has failed or itself has some quality problem during production, it will significantly reduce the charging efficiency of the charging protection circuit, and even may cause the battery of the mobile phone to explode. Although there is very small possibility for such an incident to occur, once it happens, it will damage the brand appearance of the product, and cause the mobile phone user to contradict when purchasing and using this product. Therefore, when using a wireless charger, how to avoid the severe consequence resulted from the continuous charging of the wireless charger when the high-permeability magnetic core has failed is an urgent problem to be solved.